Universitätspublikationen
Refine
Year of publication
- 2015 (1742) (remove)
Document Type
- Article (606)
- Doctoral Thesis (187)
- Working Paper (169)
- Contribution to a Periodical (164)
- Book (159)
- Report (157)
- Part of Periodical (124)
- Review (70)
- Preprint (55)
- Conference Proceeding (22)
- Part of a Book (6)
- Master's Thesis (5)
- Periodical (5)
- Bachelor Thesis (4)
- Magister's Thesis (4)
- magisterthesis (4)
- Habilitation (1)
Language
- English (866)
- German (835)
- Spanish (14)
- Italian (11)
- Portuguese (11)
- French (3)
- Multiple languages (1)
- Russian (1)
Is part of the Bibliography
- no (1742)
Keywords
- Islamischer Staat (34)
- IS (25)
- Terrorismus (23)
- Deutschland (16)
- Dschihadismus (13)
- Syrien (12)
- Terror (11)
- Irak (10)
- Islamismus (10)
- Salafismus (10)
Institute
- Präsidium (336)
- Medizin (252)
- Gesellschaftswissenschaften (230)
- Physik (185)
- Wirtschaftswissenschaften (149)
- Exzellenzcluster Die Herausbildung normativer Ordnungen (116)
- Center for Financial Studies (CFS) (115)
- Biowissenschaften (99)
- Frankfurt Institute for Advanced Studies (FIAS) (97)
- Informatik (96)
Der Auflösung mikroskopischer Verfahren ist durch die Beugungsgrenze eine natürliche Schranke gesetzt. Strukturen, die näher als die halbe Wellenlänge des verwendeten Lichts zusammenliegen, können nicht aufgelöst werden. Doch Forscher haben einen Weg gefunden, diese Grenze zu umgehen. Die entstehenden Bilder ähneln dem Pointillismus in der Malerei.
"Mehr Licht!" – so lauteten, glaubt man seinem Arzt Carl Vogel, die letzten Worte des größten deutschen Dichters und Denkers Johann Wolfgang Goethe. Aus der Sicht der Fluoreszenzmikroskopie ist das kein guter Grundsatz. Die Kernidee der Lichtscheiben-Fluoreszenzmikroskopie (LSFM) liegt in der Macht der dunklen Seite. Anders gesagt: Sie folgt dem Prinzip, dass weniger manchmal viel mehr sein kann. Die schonende Beleuchtung empfindlicher Proben bei der LSFM birgt großes Potenzial für die moderne Zell- und Entwicklungsbiologie.
Die Freisetzung von Fluorchlorkohlenwasserstoffen (FCKW) in die Atmosphäre ist seit Inkrafttreten des Montreal-Protokolls zum Schutz der Ozonschicht im Jahr 1987 reglementiert. Aber die ozonzerstörenden Gase sind äußerst langlebig. Sie können erst in der Stratosphäre, also in Höhen oberhalb von etwa zehn Kilometern, durch kurzwelliges, energiereiches Sonnenlicht gespalten werden. Messungen der FCKW und ihrer Ersatzstoffe am Institut für Atmosphäre und Umwelt erlauben es, die Lebenszeiten dieser Substanzen zu bestimmen und damit auch ihr Potenzial, die Ozonschicht zu schädigen und zur Klimaerwärmung beizutragen. Sie stellen einen wichtigen Beitrag zur Klimaforschung dar.
Aus der Redaktion
(2015)
Vom 26. Juli bis 04. August 2015 veranstaltete die Akademie BURG FÜRSTENECK die 5. Hessische Schülerakademie für die Mittelstufe (Jgs. 7-9). Fünf Jahre Schülerakademie für die Mittelstufe – ein halbes Jahrzehnt Erfahrung und Entwicklung eines Projektes mit 12-15jährigen Schülerinnen und Schülern, hessischen Hochschullehrenden und Kulturschaffenden im Kontext von Engagement und überdurchschnittlicher Begabung!
p-process nucleosynthesis via proton-capture reactions in thermonuclear supernovae explosions
(2015)
Model calculations within the framework of the so-called γ process show an underproduction of the p nucleus with the highest isotopic abundace 92Mo. This discrepancy can be narrowed by taking into account the alternative production site of a type Ia supernova explosion. Here, the nucleus 92Mo can be produced by a sequence of proton-capture reactions. The amount of 92Mo nuclei produced via this reaction chain is most sensitive to the reactions 90Zr(p,γ) and 91Nb(p,γ). Both rates have to be investigated experimentally to study the impact of this nucleosynthesis aspect on the long-standing 92Mo-problem. We have already measured the proton-capture reaction on 90Zr using high-resolution in-beam γ-ray spectroscopy. In this contribution, we will present our preliminary results of the total cross sections as well as the partial cross sections. Furthermore, we plan to measure the 91Nb(p,γ) reaction soon. Due to the radioactive target material, the 91Nb nuclei have to be produced prior to the experiment. The current status of this production will be presented in this contribution.
Triangles of groups have been introduced by Gersten and Stallings. They are, roughly speaking, a generalization of the amalgamated free product of two groups and occur in the framework of Corson diagrams. First, we prove an intersection theorem for Corson diagrams. Then, we focus on triangles of groups. It has been shown by Howie and Kopteva that the colimit of a hyperbolic triangle of groups contains a non-abelian free subgroup. We give two natural conditions, each of which ensures that the colimit of a non-spherical triangle of groups either contains a non-abelian free subgroup or is virtually solvable.
After the mass-vaccination campaign during the influenza A (H1N1) 2009 pandemic, a significant increase in narcolepsy incidence was observed initially in Scandinavia, later in other European countries and recently also in Canada. Narcolepsy is a sleep disease caused by the loss of hypocretin-producing cells in the hypothalamus. Almost all narcolepsy patients carry the HLA-DQB1*0602 allele, giving a link to an autoimmune-mediated process.
Most of the observed narcolepsy cases were correlated to the vaccination with Pandemrix, the most frequently used vaccine in the EU, and a slight connection to Arepanrix was also detected, which was distributed in Canada. Both vaccines were adjuvanted with AS03, suggesting a possible link between AS03 and narcolepsy. No narcolepsy cases were detected with MF59-adjuvanted or non-adjuvanted influenza vaccines. Recent studies reported differences between Pandemrix and Arepanrix and suggested the vaccine rather than the adjuvant as a suspect for narcolepsy development following vaccination. In addition, in China an increase of narcolepsy cases was reported to occur in absence of vaccination. Possible factors and potential additive effects that may have triggered narcolepsy after the pandemic vaccination are being reviewed in this paper.
Fossils are often anatomically and functionally compared to extant model taxa such as Pan, Gorilla, Pongo and modern Homo sapiens to put the respective fossils into the (taxonomical) context of human evolution. Therefore, knowledge of extant hominid anatomy is necessary as well as knowledge of which traits differ between sexes, populations, (sub-)species and taxa, and whether these differences are pronounced enough to separate respective groups. Dental and mandibular structures have been of particular interest in many paleoanthropological studies, simply due to the fact that these morphological structures are most abundant in the human fossil record.
Various studies have addressed questions regarding taxonomy, variation and sexual dimorphism of hominid taxa with regard to dental and mandibular size. Tooth size, however, has almost exclusively referred to crown size, with little focus on root size. The focus on tooth crowns is partly due to roots being embedded in mandibular bone which makes access difficult. With the help of micro-computed tomography (μCT) it is now possible to render virtual 3D models of dental roots and measure these models without harming the original specimens. In addition, measurements are much more precise using μCT data than previous techniques such as 2D x-rays. The present study used 3D models of 231 (first, second and third) molars and 80 mandibles of 53 Pan troglodytes verus (consisting of individuals form the Tai and Liberia populations), 14 Gorilla sp. and 13 Pongo sp. individuals to investigate molar and mandibular sizes within, and between, taxa and populations with regard to sexual dimorphism, variability and taxonomical value. Molar root size was assessed by applying 7 measurements to each molar. Mandibular size was investigated using three different measurements: overall mandibular size, mandibular robusticity (at each molar position) and 15 linear measurements. Overall mandibular size and root measurements were used to investigate the dental and mandibular size relationship. Furthermore, based on data acquired from great apes, how well fossil mandibles (including their dentition) of Australopithecus africanus, Paranthropus sp. and Homo sp. match one or multiple extant hominid taxa was examined Overall, molar root and mandibular metrics are suitable to differentiate between sexes, populations and taxa. Investigation of 40 (21 molar and 19 mandibular) different measure ments resulted in five common characteristics among Pan, Gorilla and Pongo only: firstly, molar root size sequence in root volume and root surface area (M3 < M1 < M2). Secondly, M2 as the molar with the largest cervical area, root volume, root surface area and mesial root lengths and thirdly, mandibular robusticity is larger in females than in males, yet the difference is not signifficant. Fourthly, mandibular length and premolar width are sexually dimorphic and fifthly, the best factors to discriminate between taxa are bicondyle width and molar root length. There is no generalized answer to the question which molar and/or measurement (dental or mandibular) is best to discriminate between sex or taxa in extant hominids. Moreover, size relationships differ among taxa, depending on the measurement. The overall trend, however, is that Pan is the taxa with the smallest, and Gorilla the largest, mean values. Among Pan populations, Liberian chimpanzees tend to have larger average values compared to Tai chimpanzees, with the exception of mandibular robusticity. The highest percentage of sexual dimorphic measurements is found in Pongo, yet only half of the measurements are statistically different between sexes. African apes are less sexually dimorphic compared to Pongo, and surprisingly, Gorilla is only slightly more dimorphic than Pan. The study also shows that statements and conclusions relating to \mandibular size" should not be generalized: whereas male and female Pongo do not differ significantly in overall mandibular size, they do differ in linear mandibular measurements. Moreover, Gorilla has the overall largest mandible, yet robusticity is higher in Pan, as are some linear measurements. Sexual dimorphism in overall mandibular size does not seem to reflect body mass dimorphism, whereas mandibular size appears to be related to body mass. The same was previously proposed for mandibular robusticity, yet Pan, the smallest taxa, has the most robust mandibular corpus (> Gorilla > Pongo). A substantial amount of molar measurements that positively correlate with (overall) mandibular size was found, but in African apes only. This contrasts with former studies which found no, or weak, correlations between dental and mandibular sizes. Given that the percentage of correlation is highest in Pan, and not present in Pongo, it is proposed that small jaws feature small teeth, rather than large jaws feature large teeth. This proposition assumes a size-threshold from which, when reached, dental and mandibular sizes no longer correlate, as has been previously proposed for the relationship between canine size and mandibular breadth. This assumption is further supported by the fact that the smaller and more robust Tai population shows more significant correlation compared to the less robust and larger Liberia population. Results show that fossil metrics are similar to one or multiple extant hominid taxa, depending on the measurement (dental or mandibular) used for comparison. Subsequently, the assignment to a specific sex depends on the earlier selected extant model taxa. Therefore the study questions whether choosing one model taxa for one fossil, or taxonomical group, is advisable. This study is the first to extensively investigate molar root size in extant hominids and to broadly describe differences in molar root sizes among and between taxa and therefore provides a solid database for future studies. The same applies to mandibular robusticity which has not been investigated as systematically or to such a great extent as in this work. The study specifically shows how complex the search for taxa or sex differentiating molar root and/or mandibular measurements is. Subsequently it shows that generalizations in relation to taxonomical values and statements about sexual dimorphism can be misleading.
In addition, the study contributes to the understanding of intra- and inter-population differences within Pan torglodytes verus. Furthermore, it could be demonstrated that results of a subspecies sample very likely depend on the sample composition, i.e. whether the sample consists of individuals from one or more populations. This study serves as a database for further studies investigating molar root sizes in great apes, whether these studies are investigating various relationships between taxa, population or sex, or as database to investigate functional adaptations or to examine mandibular robusticity and molar root relationships.
Biomedical data obtained during cell experiments, laboratory animal research, or human studies often display a complex distribution. Statistical identification of subgroups in research data poses an analytical challenge. Here were introduce an interactive R-based bioinformatics tool, called “AdaptGauss”. It enables a valid identification of a biologically-meaningful multimodal structure in the data by fitting a Gaussian mixture model (GMM) to the data. The interface allows a supervised selection of the number of subgroups. This enables the expectation maximization (EM) algorithm to adapt more complex GMM than usually observed with a noninteractive approach. Interactively fitting a GMM to heat pain threshold data acquired from human volunteers revealed a distribution pattern with four Gaussian modes located at temperatures of 32.3, 37.2, 41.4, and 45.4 °C. Noninteractive fitting was unable to identify a meaningful data structure. Obtained results are compatible with known activity temperatures of different TRP ion channels suggesting the mechanistic contribution of different heat sensors to the perception of thermal pain. Thus, sophisticated analysis of the modal structure of biomedical data provides a basis for the mechanistic interpretation of the observations. As it may reflect the involvement of different TRP thermosensory ion channels, the analysis provides a starting point for hypothesis-driven laboratory experiments.
The increasing number of casting shows and talent contests in the media over the past years suggests a public interest in rating the quality of vocal performances. In many of these formats, laymen alongside music experts act as judges. Whereas experts' judgments are considered objective and reliable when it comes to evaluating singing voice, little is known about laymen's ability to evaluate peers. On the one hand, layman listeners–who by definition did not have any formal training or regular musical practice–are known to have internalized the musical rules on which singing accuracy is based. On the other hand, layman listeners' judgment of their own vocal skills is highly inaccurate. Also, when compared with that of music experts, their level of competence in pitch perception has proven limited. The present study investigates laypersons' ability to objectively evaluate melodies performed by untrained singers. For this purpose, laymen listeners were asked to judge sung melodies. The results were compared with those of music experts who had performed the same task in a previous study. Interestingly, the findings show a high objectivity and reliability in layman listeners. Whereas both the laymen's and experts' definition of pitch accuracy overlap, differences regarding the musical criteria employed in the rating task were evident. The findings suggest that the effect of expertise is circumscribed and limited and supports the view that laypersons make trustworthy judges when evaluating the pitch accuracy of untrained singers.
It is now accepted that heart failure (HF) is a complex multifunctional disease rather than simply a hemodynamic dysfunction. Despite its complexity, stressed cardiomyocytes often follow conserved patterns of structural remodelling in order to adapt, survive, and regenerate. When cardiac adaptations cannot cope with mechanical, ischemic, and metabolic loads efficiently or become chronically activated, as, for example, after infection, then the ongoing structural remodelling and dedifferentiation often lead to compromised pump function and patient death. It is, therefore, of major importance to understand key events in the progression from a compensatory left ventricular (LV) systolic dysfunction to a decompensatory LV systolic dysfunction and HF. To achieve this, various animal models in combination with an “omics” toolbox can be used. These approaches will ultimately lead to the identification of an arsenal of biomarkers and therapeutic targets which have the potential to shape the medicine of the future.
The Sonic Hedgehog (SHH) pathway plays a central role in the developing mammalian CNS. In our study, we aimed to investigate the spatiotemporal SHH pathway expression pattern in human fetal brains. We analyzed 22 normal fetal brains for Shh, Patched, Smoothened, and Gli1-3 expression by immunohistochemistry. In the telencephalon, strongest expression of Shh, Smoothened, and Gli2 was found in the cortical plate (CP) and ventricular zone. Patched was strongly upregulated in the ventricular zone and Gli1 in the CP. In the cerebellum, SHH pathway members were strongly expressed in the external granular layer (EGL). SHH pathway members significantly decreased over time in the ventricular and subventricular zone and in the cerebellar EGL, while increasing levels were found in more superficial telencephalic layers. Our findings show that SHH pathway members are strongly expressed in areas important for proliferation and differentiation and indicate a temporal expression gradient in telencephalic and cerebellar layers probably due to decreased proliferation of progenitor cells and increased differentiation. Our data about the spatiotemporal expression of SHH pathway members in the developing human brain serves as a base for the understanding of both normal and pathological CNS development.
Psoriatic arthritis (PsA) is a chronic inflammatory arthritis associated with psoriasis and, despite the larger estimated heritability for PsA, the majority of genetic susceptibility loci identified to date are shared with psoriasis. Here, we present results from a case-control association study on 1,962 PsA patients and 8,923 controls using the Immunochip genotyping array. We identify eight loci passing genome-wide significance, secondary independent effects at three loci and a distinct PsA-specific variant at the IL23R locus. We report two novel loci and evidence of a novel PsA-specific association at chromosome 5q31. Imputation of classical HLA alleles, amino acids and SNPs across the MHC region highlights three independent associations to class I genes. Finally, we find an enrichment of associated variants to markers of open chromatin in CD8(+) memory primary T cells. This study identifies key insights into the genetics of PsA that could begin to explain fundamental differences between psoriasis and PsA.
Objective: To evaluate two ultrafast cone-beam CT (UF-CBCT) imaging protocols with different acquisition and injection parameters regarding image quality and required contrast media during image-guided hepatic transarterial chemoembolization (TACE).
Methods: In 80 patients (male: 46, female: 34; mean age: 56.8 years; range: 33–83) UF-CBCT was performed during TACE for intraprocedural guidance. Imaging was performed using two ultrafast CBCT acquisition protocols with different acquisition and injection parameters (imaging protocol 1: acquisition time 2.54 s, and contrast 6 mL with 3 s delay; imaging protocol 2: acquisition time 2.72 s, and contrast 7 mL with 6 s delay). Image evaluation was performed with both qualitative and quantitative methods. Contrast injection volume and dose parameters were compared using values from the literature.
Results: Imaging protocol 2 provided significantly better (P < 0.05) image quality than protocol 1 at the cost of slightly higher contrast load and patient dose. Imaging protocol 1 provided good contrast perfusion but it mostly failed to delineate the tumors (P < 0.05). On the contrary, imaging protocol 2 showed excellent enhancement of hepatic parenchyma, tumor, and feeding vessels.
Conclusion: Tumor delineation, visualization of hepatic parenchyma, and feeding vessels are clearly possible using imaging protocol 2 with ultrafast CBCT imaging. A reduction of required contrast volume and patient dose were achieved due to the ultrafast CBCT imaging.